Class Descriptor

This class is designed to describe the underlying types that will be used in the machine learning process. Any machine learning process requires a set of Features that will be used to discriminate the Label. The Label itself is the target element that the machine learning algorithms learn to predict.

Inheritance

System.Object

Descriptor

Inherited Members

System.Object.Equals(System.Object, System.Object)

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

Namespace:numl.Model

Assembly:numl.dll

Syntax

public class Descriptor

Constructors

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Descriptor()

Default constructor.

Declaration

public Descriptor()

Properties

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Features

Set of features used to discriminate or learn about the Label.

Declaration

public Property[] Features { get; set; }

Property Value

Type	Description
Property[]	The features.

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Item[Int32]

Index into features (for convenience)

Declaration

public Property this[int i] { get; }

Parameters

Type	Name	Description
System.Int32	i	Feature index.

Property Value

Type	Description
Property	Feature Property.

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Item[String]

Index intor features (for convenience)

Declaration

public Property this[string name] { get; }

Parameters

Type	Name	Description
System.String	name	Feature name.

Property Value

Type	Description
Property	Feature Property.

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Label

Target property that is the target of machine learning.

Declaration

public Property Label { get; set; }

Property Value

Type	Description
Property	The label.

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Name

Descriptor name.

Declaration

public string Name { get; set; }

Property Value

Type	Description
System.String	The name.

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Type

Base type of object being described. This could also be null.

Declaration

public Type Type { get; set; }

Property Value

Type	Description
System.Type	The type.

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VectorLength

Total feature count The number of features does not necessarily equal the number of Features given that there might exist multi-valued features.

Declaration

public int VectorLength { get; }

Property Value

Type	Description
System.Int32	The length of the vector.

Methods

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At(Int32)

Gets related property given its offset within the vector representation.

Declaration

public Property At(int i)

Parameters

Type	Name	Description
System.Int32	i	Vector Index.

Returns

Type	Description
Property	Associated Feature.

Exceptions

Type	Condition
System.IndexOutOfRangeException	Thrown when the index is outside the required range.

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ColumnAt(Int32)

Gets related property column name given its offset within the vector representation.

Declaration

public string ColumnAt(int i)

Parameters

Type	Name	Description
System.Int32	i	Vector Index.

Returns

Type	Description
System.String	Associated Property Name.

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Convert(IEnumerable<Object>, Boolean)

Converts a list of examples into a lazy double list of doubles.

Declaration

public IEnumerable<IEnumerable<double>> Convert(IEnumerable<object> items, bool withLabels = true)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<System.Object>	items	Examples.
System.Boolean	withLabels	True to include labels, otherwise False

Returns

Type	Description
System.Collections.Generic.IEnumerable<System.Collections.Generic.IEnumerable<System.Double>>	Lazy double enumerable of doubles.

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Convert(Object)

Converts a given example into a lazy list of doubles in preparation for vector conversion (both features and corresponding label)

Declaration

public IEnumerable<double> Convert(object item)

Parameters

Type	Name	Description
System.Object	item	Example.

Returns

Type	Description
System.Collections.Generic.IEnumerable<System.Double>	Lazy List of doubles.

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Convert(Object, Boolean)

Converts a given example into a lazy list of doubles in preparation for vector conversion.

Declaration

public IEnumerable<double> Convert(object item, bool withLabel)

Parameters

Type	Name	Description
System.Object	item	Example.
System.Boolean	withLabel	Should convert label as well.

Returns

Type	Description
System.Collections.Generic.IEnumerable<System.Double>	Lazy List of doubles.

Exceptions

Type	Condition
System.InvalidOperationException	Thrown when the requested operation is invalid.

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Create(Type)

Creates a descriptor based upon a marked up concrete type.

Declaration

public static Descriptor Create(Type t)

Parameters

Type	Name	Description
System.Type	t	Class Type.

Returns

Type	Description
Descriptor	Descriptor.

Exceptions

Type	Condition
System.InvalidOperationException	Thrown when the requested operation is invalid.

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Create<T>()

Creates a descriptor based upon a marked up concrete class.

Declaration

public static Descriptor Create<T>()where T : class

Returns

Type	Description
Descriptor	Descriptor.

Type Parameters

Name	Description
T

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Equals(Object)

Equality test

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
System.Object	obj	object to compare

Returns

Type	Description
System.Boolean	equality

Overrides

System.Object.Equals(System.Object)

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For<T>()

Creates a new descriptor using a strongly typed fluent approach. This initial descriptor is worthless without adding features.

Declaration

public static Descriptor<T> For<T>()

Returns

Type	Description
Descriptor<T>	Empty descriptor

Type Parameters

Name	Description
T	Source Object Type

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For<T>(String)

Creates a new descriptor using a strongly typed fluent approach. This initial descriptor is worthless without adding features.

Declaration

public static Descriptor<T> For<T>(string name)

Parameters

Type	Name	Description
System.String	name	Desired Descriptor Name.

Returns

Type	Description
Descriptor<T>	Empty descriptor

Type Parameters

Name	Description
T	Source Object Type

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GetColumns()

Available column names used to discriminate or learn about Label. The number of columns does not necessarily equal the number of Features given that there might exist multi-valued features.

Declaration

public IEnumerable<string> GetColumns()

Returns

Type	Description
System.Collections.Generic.IEnumerable<System.String>	An enumerator that allows foreach to be used to process the columns in this collection.

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GetHashCode()

Return hash

Declaration

public override int GetHashCode()

Returns

Type	Description
System.Int32	hash

Overrides

System.Object.GetHashCode()

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GetValue(Object, Property)

Returns the raw value from the object for the supplied property.

Declaration

public object GetValue(object o, Property property)

Parameters

Type	Name	Description
System.Object	o	Object to process.
Property	property	Property value of the object to return.

Returns

Type	Description
System.Object

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Learn(String)

Adds (or replaces) a label to the descriptor.

Declaration

public DescriptorProperty Learn(string name)

Parameters

Type	Name	Description
System.String	name	Name of label (must match property name or dictionary key)

Returns

Type	Description
DescriptorProperty	A DescriptorProperty.

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Load(Stream)

Load a descriptor from a stream.

Declaration

public static Descriptor Load(Stream stream)

Parameters

Type	Name	Description
System.IO.Stream	stream	Stream.

Returns

Type	Description
Descriptor	Descriptor.

Exceptions

Type	Condition
System.NotImplementedException

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New()

Creates a new descriptor using a fluent approach. This initial descriptor is worthless without adding features.

Declaration

public static Descriptor New()

Returns

Type	Description
Descriptor	Empty Descriptor.

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New(String)

Creates a new descriptor using a fluent approach. This initial descriptor is worthless without adding features.

Declaration

public static Descriptor New(string name)

Parameters

Type	Name	Description
System.String	name	Desired name.

Returns

Type	Description
Descriptor	Empty Named Descriptor.

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New(Type)

Creates a new descriptor using a fluent approach. This initial descriptor is worthless without adding features.

Declaration

public static Descriptor New(Type type)

Parameters

Type	Name	Description
System.Type	type	Type mapping.

Returns

Type	Description
Descriptor	A Descriptor.

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ToExamples(IEnumerable<Object>)

Converts a list of examples into a Matrix/Vector tuple.

Declaration

public ToExamples(IEnumerable<object> examples)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<System.Object>	examples	Examples.

Returns

Type	Description
System.	Tuple containing Matrix and Vector.

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ToMatrix(IEnumerable<Object>)

Converts a list of examples into a Matrix.

Declaration

public Matrix ToMatrix(IEnumerable<object> examples)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<System.Object>	examples	Examples.

Returns

Type	Description
Matrix	Matrix representation.

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ToString()

Pretty printed descriptor.

Declaration

public override string ToString()

Returns

Type	Description
System.String	Pretty printed string.

Overrides

System.Object.ToString()

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ToVector(Object)

Convert an object to its vector representation based on the descriptor properties.

Declaration

public Vector ToVector(object item)

Parameters

Type	Name	Description
System.Object	item	object to convert.

Returns

Type	Description
Vector	Vector representation.

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With(String)

Adds a new feature to descriptor.

Declaration

public DescriptorProperty With(string name)

Parameters

Type	Name	Description
System.String	name	Name of feature (must match property name or dictionary key)

Returns

Type	Description
DescriptorProperty	method for describing feature.